Standard preparations
Dissolve a quantity of
USP Propoxycaine Hydrochloride RS in
Solvent, and dilute quantitatively, and stepwise if necessary, with
Solvent to obtain a solution containing 0.5 mg per mL. Dilute quantitatively with
Solvent to obtain Standard preparations having the following compositions:
Standard preparation |
Dilution |
Concentration (mg RS per mL) |
Percentage (%, for comparison with test specimen) |
A |
1 in 2 |
0.25 |
0.5 |
B |
1 in 5 |
0.10 |
0.2 |
C |
1 in 10 |
0.05 |
0.1 |
Procedure
Apply separately 5 µL of the
Test preparation and 5 µL of each
Standard preparation to a suitable thin-layer chromatographic plate (see
Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel mixture. Position the plate in a chromatographic chamber, and develop the chromatograms in a solvent system consisting of a mixture of chloroform, methanol, and isopropylamine (96:2:2) until the solvent front has moved about three-fourths of the length of the plate. Remove the plate from the developing chamber, mark the solvent front, and allow the solvent to evaporate, with the aid of warm circulating air. Examine the plate under short-wavelength UV light, and again after exposing the plate to iodine vapors for a few minutes and spraying it with 7 N sulfuric acid. In each instance, compare the intensities of any secondary spots observed in the chromatogram of the
Test preparation with those of the principal spots in the chromatograms of the
Standard preparations: no secondary spot is more intense than the principal spot obtained from
Standard preparation A (0.5%), and the sum of the intensities of all secondary spots obtained from the
Test preparation does not exceed 1.0%.